Durable sander and oscillation buffer element applied to sander

ABSTRACT

A durable sander comprises a body with a drive motor, a sanding disk driven by the drive motor to perform sanding movement against the body and at least one oscillation buffer element. The oscillation buffer element includes an upper connection bar fastened to the body, a lower connection bar fastened to the sanding disk and a plurality of buffer portions bridging the upper connection bar and lower connection bar in an integrated manner. Each buffer portion has a first connection end connected to the upper connection bar, a second connection end connected to the lower connection bar and an elastic buffer section interposed between the first connection end and second connection end. The length of the elastic buffer section is greater than the distance between the first connection end and the second connection end.

FIELD OF THE INVENTION

The present invention relates to a sander and particularly to anoscillation buffer element used in a sander.

BACKGROUND OF THE INVENTION

Sanders are machine tools driven by high pressure gas or electric powerto grind the surface of objects. A conventional sander comprises a drivemotor to receive the high pressure gas or electric power as the drivingsource and a sanding disk driven by the drive motor. During sandingoperation the sanding disk is bonded to a replaceable sandpaper anddriven by the drive motor to make high speed oscillation about a movingtrack. The grinding granules of the sandpaper are is contacted with anobject to flatten and smooth the contact surface or remove other objectattached to the surface.

During the sanding disk performing the high speed oscillation, anoscillation force is generated and transmitted to the sander bodythrough a driving shaft of the drive motor. Hence operators have toapply extra effort to stabilize operation of the sander. Theconventional sander generally has at least one cylindrical pillars toconnect the sander body and sanding disk. For instance, U.S. Pat. Nos.8,231,437, 7,056,199, 3,862,520, 3,815,292 and 3,345,784 disclose asander with elastic pillars installed in four corners of the sander bodyto fasten the sanding disk. The elastic pillars can be a single strut ata greater diameter, or a cluster structure consisting of multipleelastic struts, as shown in U.S. Pat. No. 6,705,931. On the other hand,U.S. Pat. Nos. 7,771,253, 6,979,254, 6,855,040 and 5,626,510 discloseanother type of sanders with two rows of clustered vertical pillarsrespectively installed in the front side and rear side of a sandingdisk. Each row has a plurality of vertical elastic pillars. When thesanding disk oscillates, the elastic pillars share the oscillation forcegenerated by the sanding disk and reduce the vibration transferred tothe operator. Hence the operator can handle the sander easier.

Please refer to FIG. 1A for an example disclosed in U.S. Pat. Nos.7,771,253, 6,979,254, 6,855,040 and 5,626,510 that has elastic verticalpillars 11 and 11 a arranged in a row. When the sander 10 startsrunning, as shown in FIG. 1B, the sanding disk 12 is driven by a drivemotor and oscillates, and the movement of the sanding disk 12 is towedby the elastic vertical pillars 11 and 11 a. Since each elastic verticalpillars 11 and 11 a has straight structure and the same structuralstrength, in practice, when the sanding disk 12 oscillates the elasticvertical pillar 11 towards the oscillation direction deforms at asmaller amount than other elastic vertical pillar 11 a away from theoscillation direction. As a result, a lift elevation R takes place atsome edge of the sanding disk 12 during operation. In other words, themoving track of the sanding disk 12 does not locate on the same plane.In many circumstances the deformation takes place mainly at the centerportion 111 of the elastic vertical pillars 11 and 11 a. When the sander10 is operated for a prolonged duration the center portion 111 of theelastic vertical pillars 11 and 11 a could be fractured most easily. Asthe elastic vertical 11 and 11 a are individual straight structure, thelifespan is determined by its own structural strength when the sander 10is operated.

SUMMARY OF THE INVENTION

The primary object of the present invention is to solve the problems ofthe conventional sanders that the edge of the sanding disk is not inclose contact with a working object during oscillation, and the centerportion of the elastic vertical strut coupled the sander body andsanding disk is easier fractured that result in a short lifespan.

To achieve the foregoing object the present invention provides a durablesander that includes a body with a drive motor, a sanding disk driven bythe drive motor to perform sanding movement against the body and atleast one oscillation buffer element. The oscillation buffer elementincludes an upper connection bar fastened to the body, a lowerconnection bar fastened to the sanding disk and a plurality of bufferportions bridging the upper connection bar and lower connection bar inan integrated manner. Each buffer portion has a first connection endconnected to the upper connection bar, a second connection end connectedto the lower connection bar and an elastic buffer section interposedbetween the first connection end and second connection end. The elasticbuffer section is formed at a length greater than a distance between thefirst and second connection ends.

In one embodiment the first connection ends of the buffer portions areconnected to each other, and the second connection ends of the bufferportions also are connected to each other.

In another embodiment the first connection ends of the buffer portionsare separated from each other, and the second connection ends of thebuffer portion also are separated from each other.

In yet another embodiment the first connection end and second connectionend of each buffer portion are located at a same vertical axis, and theelastic buffer section of each buffer portion includes at least onedeviation section away from the vertical axis.

In yet another embodiment the elastic buffer section is formed in anarched shape.

In yet another embodiment the elastic buffer sections are mirrored abouta symmetrical axis.

In yet another embodiment the oscillation buffer element includes aplurality of first elastic buffer sections and a plurality of secondelastic buffer sections which are respectively mirrored about asymmetrical axes.

In yet another embodiment the buffer portions are located on a sameplane.

In yet another embodiment the elastic buffer section is formed at awidth increased from the first connection end towards the secondconnection end.

In yet another embodiment the first connection end is formed at a widthsmaller than that of the elastic buffer section, and the width of theelastic buffer section is smaller than that of the second connectionend.

In yet another embodiment the buffer portion at the outer side of theoscillation buffer element is formed at a width greater than that of thebuffer portion in the center of the oscillation buffer element.

In yet another embodiment the upper connection bar and lower connectionbar of the oscillation buffer element respectively include a first holeand a second hole run through by a fastening element which is screwed onthe body or sanding disk. The body has a housing to hold the drivemotor. The housing has a first fastening hole corresponding to the firsthole and run through by the fastening element. The sanding disk has asupport frame and a sanding portion fastened to the support frame. Thesupport frame includes a second fastening hole corresponding to thesecond hole and run through by the fastening element.

In yet another embodiment the drive motor includes a shaft connected tothe sanding disk.

In addition, the invention further provides an oscillation bufferelement installed on a sander. The sander includes a body with a drivemotor and a sanding disk driven by the drive motor to perform sandingmovement against the body. The oscillation buffer element includes anupper connection bar fastened to the body, a lower connection barfastened to the sanding disk and a plurality of buffer portions bridgingthe upper connection bar and lower connection bar. Each buffer portionhas a first connection end connected to the upper connection bar, asecond connection end connected to the lower connection bar and anelastic buffer section interposed between the first connection end andsecond connection end. The elastic buffer section is formed at a lengthgreater than the distance between the first and second connection ends.

The invention provides features of having an oscillation buffer elementinterposed between a body and a sanding disk of a sander. Theoscillation buffer element has an elastic buffer section which isdeformable during operation of the sander. The elastic buffer section isformed in a curved shape, hence can provide better extensibility duringdeformation to stabilize oscillation of the sanding disk so that thesanding disk can oscillate horizontally on the same plane. As theelastic buffer section has a longer deformation zone, it can reducestress concentrated on various local structures in a prolonged operationperiod so as to extend the lifespan of the sander.

The foregoing, as well as additional objects, features and advantages ofthe invention will be more readily apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a fragmentary view of a conventional sander at an initialcondition.

FIG. 1B is a fragmentary view of a conventional sander at an oscillatingcondition

FIG. 2 is an exploded view of an embodiment of the durable sander of theinvention.

FIG. 3 is a schematic view of a first embodiment of the oscillationbuffer element of the invention.

FIG. 4 is a schematic view of the sander of the invention in anoscillating condition.

FIG. 5 is a schematic view of a second embodiment of the oscillationbuffer element of the invention.

FIG. 6 is a perspective view of a third embodiment of the oscillationbuffer element of the invention.

FIG. 7 is a perspective view of a fourth embodiment of the oscillationbuffer element of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 2 and 3 for an embodiment of the durable sanderand oscillation buffer element thereof according to the invention. Thedurable sander mainly comprises a body 20 and a sanding disk 30. Thebody 20 has a housing 21 and a drive motor 22 installed in the housing21. The drive motor 22 is connected to the sanding disk 30 through ashaft 221. The sanding disk 30 can be driven by the drive motor 22 toperform sanding movement against the body 20. The drive motor 2 can bean electric motor driven by drive power converted from external powervia a power modulation circuit, or a pneumatic motor driven by highpressure gas. The sanding disk 30 has a support frame 31 and a sandingportion 32 fastened to the support frame 31. The sanding portion 32 isbonded to a sandpaper. The sander further includes at least oneoscillation buffer element 40 which has an upper connection bar 41fastened to the body 20, a lower connection bar 42 fastened to thesanding disk 30 and a plurality of buffer portions 43 bridging the upperconnection bar 41 and lower connection bar 42 in an integrated manner.The upper connection bar 41 and lower connection bar 42 of theoscillation buffer element 40 respectively include a first hole 411 anda second hole 421 run through by a fastening element 50. The housing 21includes a first fastening hole 211 corresponding to the first hole 411run through by the fastening element 50. The support frame 31 includes asecond fastening hole 311 corresponding to the second hole 421 runthrough by the fastening element 50. Hence the oscillation bufferelement 40 is fastened to the body 20 and sanding disk 30.

In addition, referring to FIG. 3, each buffer portion 43 has a firstconnection end 431 connected to the upper connection bar 41, a secondconnection end 432 connected to the lower connection bar 42 and anelastic buffer section 433 interposed between the first connection end431 and second connection end 432. The elastic buffer section 433 isformed at a length greater than the distance a between the firstconnection end 431 and second connection end 432. The first and secondconnection ends 431 and 432 of each buffer portion 43 are located at asame vertical axis X1. The elastic buffer section 433 of each bufferportion 43 also includes at least one deviation section 434 away fromthe vertical axis X1. The elastic buffer section 433 can be formed in anarched shape with a continuous smooth curve. In this embodiment thebuffer portions 43 of the oscillation buffer element 40 are located on asame plane. When the sander is operated the drive motor 22 drives thesanding disk 30 to oscillate through the shaft 221, and the oscillationbuffer element 40 connected the body 20 and sanding disk 30 alsodeforms. Referring to FIG. 4, take the sanding disk 30 moving rightwardagainst the body 20 as an example for discussion, the lower connectionbar 42 drawn by the sanding disk 30 also is moved rightward, and theelastic buffer section 433 connected to the second connection end 432also is driven and deforms rightward. If the sanding disk 30 is movedleftward against the body 20, the elastic buffer section 433 alsodeforms leftward. Due to the length of the elastic buffer section 433 isgreater than the distance a between the first connection end 431 andsecond connection end 432, the deformation zone of the elastic buffersection 433is longer to reduce the stress generated by the deformationand the deformation amount of each unit length. Moreover, the elasticbuffer section 433 has sufficient extensibility to make the sanding disk30 to oscillate steadily and horizontally on the same plane duringmovement.

Referring to FIGS. 2 and 3, the first connection ends 431 of the bufferportions 43 are connected to each other, and the second connection ends432 of the buffer portions 43 also are connected to each other. Sincethe first and second connection ends 431 and 432 of different bufferportions 43 are connected to each other, the connection of the bufferportion 43 with the upper connection bar 41 or lower connection bar 42is enhanced, and total structural strength of the oscillation bufferelement 40 also increases. In another embodiment the first connectionends 431 of the buffer portions 43 are separated from each other and thesecond connection ends 432 of the buffer portions 43 are separated fromeach other, as shown in FIG. 5. Hence the buffer portions 43 of theoscillation buffer element 40 also are separated from each other.

In terms of arrangement of the buffer portions 43 of the oscillationbuffer element 40, FIG. 3 illustrates an embodiment in which theoscillation buffer element 40 includes a plurality of elastic buffersections 433 mirrored about a symmetrical axis X2. FIG. 6 depictsanother embodiment in which the oscillation buffer element 40 includes aplurality of first elastic buffer sections 433 a and a plurality ofsecond elastic buffer sections 433 b which are respectively mirroredabout a symmetrical axis X2.

During operation of the sander, the lower half portion of theoscillation buffer element 40 usually deforms at a greater amount thanthe upper half portion. In order to enhance the structural strength ofthe oscillation buffer element 40, referring to FIG. 7, the firstconnection end 431 can be formed at a width W1 smaller than the width W2of the elastic buffer section 433, and the width W2 of the elasticbuffer section 433 is smaller than the width W3 of the second connectionend 432. Or the width of the elastic buffer section 433 can be increasedfrom the first connection end 431 towards the second connection end 432.On the other hand, the width of the buffer portion 43 a at the outerside of the oscillation buffer element 40 is greater than the width ofthe buffer portion 43 b in the center of the oscillation buffer element40.

In short, the durable sander of the invention provides a feature with atleast one oscillation buffer element interposed between the body andsanding disk. The oscillation buffer element has an elastic buffersection which can deform during operation of the sander. The elasticbuffer section is formed in a curved structure to provide betterextensibility during deformation to stabilize horizontal oscillation ofthe sanding disk on the same plane and maintain sanding quality.Comparing with the conventional vertical straight elastic strutstructure, the elastic buffer section has longer deformation zone toreduce stress concentrated on local structures in prolonged operationperiod. As a result, overall lifespan of the sander is prolonged.

What is claimed is:
 1. A durable sander, comprising: a body holding adrive motor inside; a sanding disk driven by the drive motor to performsanding movement against the body; and at least one oscillation bufferelement which includes an upper connection bar fastened to the body, alower connection bar fastened to the sanding disk and a plurality ofbuffer portions bridging the upper connection bar and the lowerconnection bar in an integrated manner; each of the plurality of bufferportion including a first connection end connected to the upperconnection bar, a second connection end connected to the lowerconnection bar and an elastic buffer section interposed between thefirst connection end and the second connection end, the elastic buffersection being formed at a length greater than a distance between thefirst connection end and the second connection end.
 2. The durablesander of claim 1, wherein the first connection ends of the bufferportions are connected to each other and the second connection ends ofthe buffer portions are connected to each other.
 3. The durable sanderof claim 1, wherein the first connection ends of the buffer portions areseparated from each other and the second connection ends of the bufferportions are separated from each other.
 4. The durable sander of claim1, wherein the first connection end and the second connection end ofeach buffer portion are located at a same vertical axis, the elasticbuffer section of each buffer portion including at least one deviationsection away from the vertical axis.
 5. The durable sander of claim 1,wherein the elastic buffer section is formed in an arched shape.
 6. Thedurable sander of claim 1, wherein the elastic buffer sections aremirrored about a symmetrical axis.
 7. The durable sander of claim 1,wherein the oscillation buffer element includes a plurality of firstelastic buffer sections and a plurality of second elastic buffersections which are respectively mirrored about a symmetrical axis. 8.The durable sander of claim 1, wherein the buffer portions are locatedon a same plane.
 9. The durable sander of claim 1, wherein the elasticbuffer section is formed at a width increased from the first connectionend towards the second connection end.
 10. The durable sander of claim1, wherein the first connection end is formed at a width smaller thanthat of the elastic buffer section, and the width of the elastic buffersection is smaller than that of the second connection end.
 11. Thedurable sander of claim 1, wherein the buffer portion at an outer sideof the oscillation buffer element is formed at a width greater than thatof the buffer portion in the center of the oscillation buffer element.12. The durable sander of claim 1, wherein the upper connection bar andthe lower connection bar of the oscillation buffer element respectivelyinclude a first hole and a second hole run through by a fasteningelement which is screwed on the body or the sanding disk.
 13. Thedurable sander of claim 12, wherein the body includes a housing to holdthe drive motor, the housing including a first fastening holecorresponding to the first hole and run through by the fasteningelement.
 14. The durable sander of claim 12, wherein the sanding diskincludes a support frame and a sanding portion fastened to the supportframe, the support frame including a second fastening hole correspondingto the second hole and run through by the fastening element.
 15. Thedurable sander of claim 1, wherein the drive motor includes a shaftconnected to the sanding disk.
 16. An oscillation buffer elementinstalled on a sander which includes a body with a drive motor and asanding disk driven by the drive motor to perform sanding movementagainst the body, comprising: an upper connection bar fastened to thebody; a lower connection bar fastened to the sanding disk; and aplurality of buffer portions bridging the upper connection bar and thelower connection bar in an integrated manner, each of the plurality ofbuffer portions including a first connection end connected to the upperconnection bar, a second connection end connected to the lowerconnection bar and an elastic buffer section interposed between thefirst connection end and the second connection end, the elastic buffersection being formed at a length greater than a distance between thefirst connection end and the second connection end.
 17. The oscillationbuffer element of claim 16, wherein the first connection ends of thebuffer portions are connected to each other and the second connectionends of the buffer portions are connected to each other.
 18. Theoscillation buffer element of claim 16, wherein the first connectionends of the buffer portions are separated from each other and the secondconnection ends of the buffer portions are separated from each other.19. The oscillation buffer element of claim 16, wherein the firstconnection end and the second connection end of each buffer portion arelocated at a same vertical axis, the elastic buffer section of eachbuffer portion including at least one deviation section away from thevertical axis.
 20. The oscillation buffer element of claim 16, whereinthe elastic buffer section is formed at an arched shape.
 21. Theoscillation buffer element of claim 16, wherein the elastic buffersections are mirrored about a symmetrical axis.
 22. The oscillationbuffer element of claim 16 further including a plurality of firstelastic buffer sections and a plurality of second elastic buffersections which are respectively mirrored about a symmetrical axis. 23.The oscillation buffer element of claim 16, wherein the buffer portionsare located on a same plane.
 24. The oscillation buffer element of claim16, wherein the elastic buffer section is formed at a width increasedfrom the first connection end towards the second connection end.
 25. Theoscillation buffer element of claim 16, wherein the first connection endis formed at a width smaller than that of the elastic buffer section,and the width of the elastic buffer section is smaller than that of thesecond connection end.
 26. The oscillation buffer element of claim 16,wherein the buffer portion at an outer side is formed at a width greaterthan that of the buffer portion in the center.